Problem: Simplify the expression. $(t^{4}-2t^{3}+7t^{2})(-7t^{4}+t)$
Answer: First use the distributive property. $ t^4 (-7 t^4) + t^4 ( t) - 2 t^3 (-7 t^4) - 2 t^3 ( t) + 7 t^2 (-7 t^4) + 7 t^2 ( t) $ Simplify. $-7t^{8}+14t^{7}-49t^{6}+t^{5}-2t^{4}+7t^{3}$